It will serve to make the point clearer if we contrast our genuine a priori judgement with an empirical generalization, such as “all men are mortals.” Here as before, we can “understand” what the proposition means as soon as we understand the universals involved, namely “man” and “mortal.” It is obviously unnecessary to have an individual acquaintance with the whole human race in order to understand what our proposition means. Thus the difference between an a priori